Monday 14 April 2014 11.20 EDT
First published on Monday 14 April 2014 11.20 EDT

Ukrainian government uses force

Ukraine carries out its threat and uses the army to take on pro-Russian activists occupying government buildings in the east of the country. The risk is that moving against them will trigger large-scale violence and – as Russia has warned – even civil war. Many in eastern Ukraine already dislike the interim government in Kiev that replaced the administration of the former president Viktor Yanukovych, even if they are not separatists or active in the protest movement. Large-scale fighting could force the Ukrainian authorities to suspend the constitution and delay next month's presidential elections – a potentially important landmark. It could also trigger direct Russian intervention. "They are tempted to use force against the attackers," warned the Kiev-based analyst Mykola Riabchuk, "but must also be careful not to give an excuse for a Russian intervention."

Russia intervenes directly

Having in effect annexed Crimea last month, Russia has repeatedly declared it has no intention of sending troops into Ukraine. The president, Vladimir Putin, will not want to risk starting a war. Still, the Duma has authorised him to intervene militarily if Moscow's interests are threatened, and Putin says these include Ukraine's Russian speakers – though the vast majority are ethnic Ukrainians. He could respond to a manufactured "appeal for help" from pro-Russian "compatriots", supporters of what he calls "federalisation". But a fully fledged invasion would be problematic: Ukrainian forces would be in a better position to resist Russia in mainland Ukraine than in Crimea, where Russian units were already stationed. Support for Russian action is also far weaker in Ukraine than in Crimea. Overall, Moscow wants Ukraine to stay weak and under its influence, and will try to avoid an election that produces a new president with a strong mandate and helps set Ukraine back on track to normality. Western governments have highlighted the presence of 35,000-40,000 Russian troops near the border with Ukraine equipped with combat aircraft, tanks, artillery and logistical support units. For the moment though, Russia's involvement looks more likely to remain covert, even if its denials are increasingly implausible.

US and EU impose tougher sanctions

Highly likely. Washington has made clear that it will step up sanctions against Moscow if pro-Russian military actions in eastern Ukraine continue. Sanctions in energy, banking and mining could all be on the table. Russia's central bank has admitted to a net capital outflow of $63bn in the first three months of this year – as much as for the whole of 2013. Russia's exclusion from the G8 has already been a heavy blow to its prestige. "Putin's behaviour suggests he believes that the US and the EU have neither a concept for stabilising Ukraine nor the appetite to bail it out economically," said John Lough of Chatham House. "He also does not appear to take seriously the threat of strong western economic sanctions." But the EU remains divided. Germany is reliant on Russia for gas, France has defence contracts with the country, and there is heavy Russian investment in the UK finance industry. It will be harder to overcome those divisions in the absence of overt Russian intervention, rather than the less clear-cut situation of involvement behind the scenes.

"If Russia can conceal its hand, it will be difficult for the Europeans to respond directly to such developments," said the Stratfor strategic consultancy. "After all, how do you impose sanctions on suspected Russian covert backing for armed groups, and who would want to lead that investigation?"

Nato intervenes

Extremely unlikely. The alliance has repeatedly expressed concern about the Ukraine crisis. Anders Fogh Rasmussen, its secretary general, has called it "the greatest challenge to Europe's security in a generation" and warned of "grave consequences" if Russia were to invade. Nato needs to talk tough, especially after failing to prevent the annexation of Crimea, and to reassure its eastern members, especially the three Baltic states, of its readiness to defend them. It has halted all co-operation with Russia. But there is no prospect of Nato deliberately starting a war.

Diplomatic options

In a complex and fast-moving situation it is hard to predict what will happen next. Four-party talks planned for Thursday in Geneva will be the first time since the start of the crisis that Russian, EU, US and Ukrainian leaders have met together. The growing unrest and destabilisation in eastern Ukraine is likely to strengthen Moscow's hand as it pushes for a political solution that serves its interests – and those of pro-Russian Ukrainian groups who want a new constitution creating a federal system of government with greater autonomy for the regions.